Long term side effects

Sup gents,

My grandfather is suffer from Alzheimers. With that said my old man is worried that he would get it to.
So obviously being concerned I've tried to do some research regarding this matter. In all the research I've done on the net regarding test and so on I've come across a couple of sites where they believe that low test levels contribute to alzheimers and that TRT can actually prolong or prevent this illness.
I've tried to find out exactly what the pros and cons are long term but there doesn't seem to be conclusive concrete studies at the moment.
Does anyone have any experience with TRT that can shed some light on this matter?

Thanks